Synchronizing device



1 l. E. cox

March 17, 1925. I a 1,530,304

SYNCHRONIZING DEVICE Filed 'Api'il 24 1923 1/6/715 [3880 if Cox,

ms/ zcarne alternator 2 having passed Mar. 17,:1925.

UNITED STATES 1,5303% PATENT OFFICE.

ISAAC n cox, or ST. LOUIS, 'mssoonn srmcnnonizmo DEVICE.

Application filed April 24, 1923. Serial No. 634,390.

To all whom it may cmwern:

Be it known that I, Isaac E. Cox, 8 citizen of the United States, residing at the city of St. Louis, in the State of Missouri, have invented certain new and useful Improyements in Synchronizing Devices, of which the following is a; specification. 04

M invention relates to impr ements in sync ronizing devices and has for an object to provide an improvedsyn chronizing device which is operative to compare the frequencies of two alternating electromotive forces and thereby automatically to control the source of one electromotive force so as to bring the frequency thereof to its 5 nclironous value relativelyto the other e ectromotive force with a positive anddefinite action which is dependent upon the difier-' ence between the, frequencies of the electro-' motive forces. Another object of my invention isto provide an improved synchronizing device for automatically controlling the operation of connecting one source of alternating electromotive force to another source of alternating electromotive force so that the connection can be efl'ected only when the electromotive forces have substantially the same frequency and are substantially in phase.

This application is a continuation in part of my copending application Serial No. 499,970, filed September 12, 1921, for synchronizing device, certain of the sub ect matter in said. prior application being incorporated in this application together with certain additional subject matter.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims. v

In the single figure of the accompanying drawing, I have illustrated an embodiment of my invention as up lied to a three phase alternating current e ectric system, comprising an alternating current electric c-ircuit such as a bus 1 to which may be connected a plurality of dynamo electric machines or sources of alternating electromotive force in parallel as is well known to the art, I have illustrated only one dynamo electric machine such as a sychronous generator or .a rotating field and adapted to be connected in circuit with the bus 1 by any suitable circuit controlling means 3 arranged to control a circuit 4 between the bus 1 and the alternator 2. For closing purposes, the circuit controlling means 3 preferably comprises an electronsponsiveactuating means such as a closing coil 5 arranged to be energized from a control bus 6. The circuit controlling means 3 I is illustrated as an e ectric switch or circuit breaker'of the latched closed type arranged to be released by any suitable electroresponsive tripping means 7 in a maner well known to the art. The switch 3 may also include auxiliary switches 8 and 8' arranged to be controlled'thereby so as to be closed when the'switch 3 is open and open when the switch 3 is closed.

The alternator 2 may be driven by any suitable driving means herein illustrated as a prime mover 9 of the turbine type direct connectedto the rotating field of the alternator 2 by a shaft 9. For starting and stopping purposes, the prime mover 9 comprises an admission or gate v alye lO arranged to be act uatcd by any suitable means such as a drivingmechanism ll z'irranged to be operated by a split field motor 12 which is adapted to be connected to the control bus 6 by a switch 13. For interrupting the circuit of the motor 12-,when the desired valve open or closed position is effected, limit switches 14 and 15,

controlled by a traveler 16 which is associated with the driving mechanism 11, are provided; The prime mover starting control mechanism also includes suitable switching means such as a drum controller 17 arranged to be operated by the motor 12 through the driving mechanism-11 to control certain electric circuits at predetermined speeds of the prime mover 9, as will hereinafter appear. The drum controller 17 comprises 'conductively connected segments 18 and 19 arranged to be engaged by con tacts 20 and 21 respectively after a predetermined opening movement of the valve 10, and a segment 22 conductively connected to segment 19 and arran d to be engaged by contact 23 after furt er movement of the valve 10 to the open position.

For controlling the speed of the prime mover 9 and therefore the frequency of the alternator 2, suitable speed contro maybe provided, such as a throttling or speed control valve 24 which-may be operated directly by suitable speed responsive means such as a centrifu -mechanism 25 arra to be driven by epnme mover 9, or irectly through a pilot valve 26 armeans llO 1 the frequency v the 81ft meter 2 27 is arranged ,to

ranged t'o sive means 25, the effect of which may 'be transmitted to the valve 26 through links 26. For controlling the speed of the alternator so as to bring the electromotive force thereof to its synchronous value relatively to the electromotive forceof the bus 1, I proride, in accordanm with my invention, means such as a dynamo electr c machine comprising two cooperating movable memb81327 and 28 operative with a positive and definite action to compare the frequencies of the electromotive forces and to produce a corrective eflect dependent upon the d1fier-' ence between the frequencies. The member A be driven from the shaft 9' for example, at,a s eed pr'oportionalto of the e ectromotive force of and, for this purpose, may be men .itedon a shaft 29 in driving relationship 'wi.-h shaft 9' through suitable gears 30. The member 27 may rotor of a rotat' field synchronous motor orlike tue rotor t ifan induction motor. For example, the member 27 may comprise a magnetic member arranged to be energized by a windingBl so as'to provide at least twofixed po '5 of opposite polarity, and in addition a short-circuitdd squirrel cage or amortisseur winding 32, or merely the windi 32 alone. The preferred construction em dies both windings in order to secure the best torque conditions and thereby a positive'and definite action on a relatively small difference between the frequencies.

The winding 31 may be energized from the control.bus"6 through collector rings 33. The cooperating member 28-is constructed like the stator of a synchronous or induction motor and has a winding of the usual polyphase type arranged to be connected in circuit with the bus 1 either directly through conductors 34 or through potential transformers, according to the bus voltage,'by any suiiable switching means-such as a contactor 35. For closing purposes, this contactor is arran ed; to be operated by a closing coil 36, and the contactor 35 preferably controls an auxiliary switch 37 which is open when the contactor is open and closed when (he contactor is closed-for a purpose hereinafter set forth.

The cooperating member 28 is secured to a rotatablv mounted shaft 38 rotation of which is e ecti e to controlthe prime mover speed control means so as to provide a corrective e'l'ect or speed adjustment supplementar to tie control exertr by the centrifuge mechanism and thereby to bring the frequency of the alternator 2 to its synchronous value. This corrective eiiect may be applied to the pilot valve 26 and thus to the speed control valve 24 by any suitable means such as a jack-shaft 39, arranged to actuate an adjusting member 40 associated with the be controlledby the speed responbe constructed like the centrifugal mechanism 25 and thelinks 26'. Movement of the member 40' in either direction superimposes on the action of the cen trifugal mechanism 25 an additional action to effect a change in the speed of the prime mover. This action will be dependent upon the speed of the member 28, which is in turn dependent upon the difference between the frequencies of the alternator and bus voltages, for the member 28 will rotate at a speed corresponding tov this difference between the frequencies.

In order that the switch 3 may be closed referabl y contacts 42 are so disposed relatively to the angular position of member 28 that engag mentof the contacts '42 by the contact member 41 occurs substantially when the electromotive forces are in phase and lasts for a time which increases as the difierence between the frequencies, that is to say, the speed of the member 28, decreases.

The winding 31* of the rotor member 27 and the fieldof the alternator 2 may be energized from the control bus 6 or a separate excitcr bus if desired. For connecting the alternator field and the winding 31 to the control bus 6, I provide suitable means such as a field switch 46 arranged to be controlled y effect the encrgization of the alternator field of the prinic. mover.

means such as a closing coil 47 and the switch 46 may be of the latched closed type artheprime mover starting means so as to ranged to be released by any suitable electroresponsive means 4-8 in a manner well known to the art. V

In order that the electromotive force of the alternator'2 may be'the same as the electromotive force of the bus 1, when the electromotive forces thereof have the same frc quency and are in phase, any suitable voltage regulating means may beemployed; The voltage regulating means may be of the type operative in response to the relative values of the, electromotive forces, or with substantially constant bus. voltage, of the type operative in response to the electromotive force of the alternator only, as is well known to the'ait. The voltage regulating means 49 illustrated, is of the latter type and 1s arranged to control the field excita tion of the alternator 2. The voltage regulator 49 comprises a field rheostat 50 arranged to be actuated by a split field motor controls the v motor 51 which is adapted to be energized from the control bus 6 when the field switch 46 is closed, b any suitable means such as a contact malZin voltmeter 53 E Operative in response tot e electromotlve orce of the al Assuming the parts in sitiorr as shown J in the drawing and that t 1e alternator 2 is "tobe Iconnected to the bus 1 in parallel with ;another source of alternating electromotive force, the operation of the ll'lustrated em-- ent of my invention is as follows: Switc 13 is moved to the right thereby conheating the motor 12 to the control bus 6 throu h a circuit including the limit switch an the lower portion of thesplit field winding of the motor 12. This energizes the motor 12 so asto rotate'in a direction to actuate the driving mechanism 11 and move the starting control valve 10 to open posi- I tion thereby admitting the energizing agency such as steam or water to the prime mover 9.

During the opening movement of the valve 10, the traveler 16 1s raised and releases the l 2 limit switch 14 which returns to the closed "position so that the motor 12 may be energized .toiclose the valve 10 when it is desired to stop the prime mover 9. When the traveler 16 reaches a position corresponding {to apredetermined valve opening, it opens the l1mit switch 15 thereby V interrupting the motor circuit and deenergizing the motor 12 so as to prevent jamming the valve mechamam. v i p Actuation of the driving mechanism 11 effects movement of the'dr'um controller 17 in a direction such thatQupOn a p rcdcten, :mincd valve opening, tha is to say a predetermined speed of the prime mover 9, segments 18 and 19 of the drum controller engage the contacts 20'and 21.

. 46, conductor When this occurs, the closing coil 47 of the field switch 47, conducto'r'55, contact 20, controller segments l8 and 19, contact 21, conductor 56, auxiliary switch 8 and conductor- 57.- Upon energization of the coil 47, field switch 46 closes thereby connecting the rotating field of the alternator 2 to the control bus 6 in a circuit, comprising conductor 54, field switch 58, alternator field collector rings 59, conductor 60, rheostat 50, conductor 61, field switch 46 and conductor 62. The predetermined speed of the rime mover at which field switch 46 is close may be in general any speed below synchronous speed, but with a-steam turbine as rime mover, the field switclrAG is preferab y not closed until the turbine has attained substantially its critical speed. When the field switch 46 is closed, the winding 31 of the rotatingmember 27 is also energized, the

winding 31 being in a circuit across, conductorsa8 and 60. Thiscircuit is conductor 63, auxiliary switch 8, conductor 64, collector rin 33 and conductor 65. The member 27. t we constitutes a'rot'ating electromagnetic field whichis driven at a speed proportional to the frequency of the a ter- 1 of the prime contactor 35, the energizing winding of the rotatable member 28 is connected to the bus 1 through collector rings 68 and there is set up a field which rotates relatively to the member '28 at a speed. dependent upon the frequency of the'bus volta e. The interaction of this field-{and the fie d of the member 27 results in rotation of the member 28 at a speed proportional to the difference between the frequenciesof the alternator. and bus voltages. With the squirrel cage winding '32 alone, the member 28 will cooperate 'with the member 27 in a manner similar to an induction motor and with the squirrel cage winding 32 in addition to the winding 31, anincreased starting torque is assured to drive the member 28.

The direction in which the member 28 is caused to rotate will depend upon whether the frequency of the alternator voltage is greater or less than that of the bus voltage. As the member i 28 rotates, it will, through-the jack shaft 39, the adjusting member 40 and links 26, produce a corrective effect which is superimposed on the action of the centrifugal mechanism 25 to vary the speed of the prime mover 9. This corrective effect being proportional to the difference between the frequenc'es of the clectromotive forces to be synchronized,

changes the speed of the prime mover 9so as to eliminate'the difference between the frequencies, that is to say to ternator 2 to synchronous speed. I

As the member 28 rotates, the contact i member'41 carried thereby will cngage contacts 42 for a time dependent upon the'spoed of the member 28, that isto say, thediflerence between the frequencies of the alterbring the al{ .:di erence between the fr lnat or and bus voltages. hen-contacts 42 are engaged by switch member 41, the energizing Winding of the relay 43 is connect- 'ed to the bus 6m a circuit, comprising conductor 57, auxiliary switch 8, conductor 56,

contact 21, controller segments 19 and 22,

contact 23, conductor I56; contacts 42 and contact member 41, conductor 69, auxiliary switch, 37,- conductor 70," energizing windin of relay 43 and conductor 67. As the uencies decreases, thecontactgmember 41 wi I engage contacts 42? a longer time, which is, when the frequenciesare substantially: thesame, sutticient to permit the relay to move contact controlling member 45 to engage contacts 44. When this occurs, the closing cnit 5 of .vthe 'switch 3 is connected to the bus 6 in a circuit, comprising cohductorfii', auxiliary switchj8,'conductor 71, closing coil 5, conductor 72, 'contact cpntrolling'member 45, contacts;44 and'conductor 67 Upon the energizat ion,of the closing coil 5, the switch a 3,1s;closed,and the alternator 2 the bus 1.

connected to When the switch is closed and latched,

. auxiliary switches 8 and- 8" are opened contacts 42'when starting, it will be impossible to energize the relay 43 and connect the alternator 2 to the bus 1. In other words, at starting whenthe difference between the frequenc'es is great, it is impossibleto energize the relay 43 until the member'28 has been energized so as to rotate and more contact member 41.

To stop the prime mover 9, the switch 3 is tripped open and the switch 13 is moved to the left, thereby connecting the motor 1-2 to the control bus 6 through a circuit including the limit switch 14 and the upper portion of the split'field winding of the motor 12. This energizes the motor 12 t rotate in a direction to actuate the di'ivin mechanism 11 and move the starting contrbl valve to closed position. During the closing movement, the traveler 16 releases the limit switch so that itmay close and o ens the; limit switch 14 so as to deenergize he mo-l tor 12 when the valve 10 reaches closed po-; sition, and the parts are again in position' for starting" the prime mover, as S1()\\'11 in the drawing.

While I have herein shown anddescribul one embodiment of my invention, 1 do not desire to be limited to the exact arrangement shown and descrbed, but seek to cover in the appended claims all modifications which come within the true spirit and scope of my invention.

\Vhat I claim as new and desire to secure by Letters Patent of the United States, is 1. In an electric system wherein two sources of alternating electromotive force are to be synchronized and where'n means is provided for driving one of said sources, a 4

member arranged to bedriven-at a speed proportional to the frequency of the source associated with said driving means, ineans 2. In an electric system wherein two sources of alternatin are to be synchronize provided for driving synchronizing means comprisinga dynamo electric machine having a movable member arranged to be driven at aspeed propor-' tional to the frequency of the source associated with said driving means, means arranged'to rotate at a speed dependent upon the difference between the frequencies of the electromotive forces'comprising a movable electromagnetic member havng a winding arranged to be energized by the other source, and means for controlling the speed of said driving means arranged to be con-- trolled by said electromagnetic member to bring said driving in? speed.

-3. In an electric system wherein two sources of alternating clectromotive force are to be synchronized and wherein means is provided for driving one of said sources, synchronizing means coi'nprising a switch 1' or connecting said sources together, a member having a winding arranged to be energized upon a predetermined speed of said driving means, said memberibeing arranged elcctromotive force and wherein means to be driven at a speed pro )ortional tothe frequency of the sourc 'assof iatetr with said dr ving means, acoop rating member having a winding arrangel to be connected in circuit with the other euros and to rotate ata speed dependent u on'the difference between the frequencies .ofthe elect romotive forces, and means for closing said switch only when the speed of said cooperating one of said sources,

.3 to synchronous member is less than a predetermined value.

4. In an electric system wherein two sources of alternating electrmnotive force are to be synchronized and wherein means isprovided for driving one of synchronizing means comprising a switch said sources,

portional' to the frequency of t e source associated withsai'd driving means, means movable at a speed dependent upon the difference between the frequenciesof the elec-' tromotive forces comprising a movable electromagnetiomember having a winding arranged to be connected in circuit with the other source, and means operative to effect the closlngof said switch only after said windingh'as been energized and the speed of said movable means is 'leSs than a predetermined value.

5. an, electric system wherein two sources of' alternating electromotive force are to 'be synchronized and wherein means is provided for driving one of said sources, synchronizin means comprising a dynamo electric machine having a movable member arranged to ,be driven at a speed proportional to the frequency of the source associated with said driving means and means arranged to rotate at a speed dependent upon the difference between the frequencies 0 the electromotive forces comprising a cooperating movable member having a winding adapted to be energized by the other of said sources, means forcontrolling the speed of said driving means arranged to be controlled by said cooperating member, and means controlled by said cooperating member for connecting said sources together when the electromotive forces thereof are in synchronism.

6; In an electric, system wherein two sourcesof alternatin electromotive force are to be synchronize and wherein means is provided'for driving one of said sources, synchronizin means comprising a dynamo electric machine having a movable member arranged to be driven at a speed proportional to the frequency of one source an means arranged to rotate at a speed dependent upon the difierence between the frequencies of'the electromotive forces comprising a cooperating movable member having a winding adapted to be connected to the other source, means 'roperative in response ,to a predetermined speed of said driving means to connect said winding to said other source, means for controlling the speed of said driving means arranged to be controlled by said cooperating member, and means controlled by said cooperating member for connecting said sources together when the electromotive forces thereof are in synchronism. I

7; In an electric system wherein two sources of alternating electromotive force are to be synchronized and wherein means is provided for driving one 0 f sa-id sources, synchronizing means comprislng a member arranged to be driven at a speed proportional to the frequency of the, electro motive force of one source, means arranged to rotate at a speed proportional to the difference between the frequencies of the electromotive forces comprising a' cooperating member provided witlr'a winding adapted to be energized by the other source, means for controlling the speed of said driving means arranged to be controlled b said cooperating member to bring sai driving means to synchronous speed, and means controlled by said cooperating member'for connecting said sources together when the-electromotive forces thereof are in synchronisin- 8. In an electric system wherein two sources of alternating electromotiveforce are to be synchronized and wherein means 18 provided for driving one of said sources,

synchronizing means comprisingba dynamo.

electric machine having a mova le member provided with a tional to the frequency of one sourceand means arranged to rotate at a speed dependent upon thedifi'erence between the frequencies of the electromotive forces comprising do a cooperating movable member havm a winding adapted to be connected to theo er source, means for controlling the speed of said driving means arranged to be controlled by said cooperating member, and means controlled by said cooperating memberfor connecting said soufces together when the electromotive forces tlfereof are in synchronism. 9. In an electric system wherein two sources of alternating electromotive force are to be s nchronized and wherein means is provided or driving onepf the sources, syn chronizing means comprising1 a switch for connecting the sources toget er, a member arranged to be driven at a speed propor- 5 tional to the frequency of the source associatedwith said driving means, means arranged to rotate at a s eed dependent upon the difference between t tween the frequencies of the electromotive 12o forces is less than a prcdetermined'value.

10. In an electric systenu wherein two sources of" alternating electromotive force are to be synchronized and wherein means is provided for driving one of said sources, 125

synchronizing means comprising a member arranged to provide magnetic poles of a fixed polarity and to be drivenat a speed proportional to the frequency of the elec tromotive force of the source associated with 130 short-circuited winding 8 and arranged to be driven at a speed propore frequencies of the electromotlve forces comprising a cooperatwinding to said other source ar- 25 mg member bein said driving means, a coo rating member having a winding arrange to be connected -to the other of said sources and to rotate at? a speed dependent upon the difierence .between the forces, means for controlling the speed of said dri'vingmeans arranged to be controlled ,by said cooperating member to brin said driving means to synchronous s and means controlled bysaid cdoperating memhaving an energizing win ing and arranged I wherein two to be driven at a speed proportional to the' frequency of thesource associated 'with said driving means, a cooperating member having an energizing winding ada ted to be energized by the other source, sai cooperatarranged to rotate at a speed proportiona to the difference between t e frequencies of the electromotiveforces, means adapted to be operated to startsaid driving means and arranged to'efi'ectenergization ofsaid windin means for controlling the s eed of said driving means arranged to controlled by said cooperating member to bring said driving means to synchronous speed; and means controlled by said cooperating member for connecting said sources together when said driving means has attained synchronous speed.

(12. In an electric system wherein two sources ofalternatin electromotive force are to be synchronize and wherein means is provided for driving one of said sources, synchronizing means comprising an electromagnetic member arranged to provide poles of a fixed polarit and to be driven at a speed proportiona to the frequency of the source associated with said driving means, means for controlling the starting of said driving means arranged to effect the encrgization of said member, a cooperating electromagnetic member having an energizing winding. arranged to be connected to the other source at a predetermined speed of said drivingmeans, said cooperating electromagnetic member being arranged to rotate at a speed proportionalto the difference between the frequencies of the electromotiveforces, means =controlled by said cooperating electromagnetic member operative to control the speed of said driving means whereby to bring the same to synchronous speed, and means controlled by said cooperating electromagnetic member for connecting said sourcestogether when said driving means has attained synchronous speed.

13. In an electric system wherein the elecrequencies of the electromotive' said member is synchronized with the electromotive force of an electric circuit andwherein a prime 1 mover is provided-for driving'said alternator, a switch for connecting said alterto n'ator to said circuit, a dynamo electric machine comprising a rotor arranged to be driven by said prime mover at a speed proportional to the frequency of the alternatorandlmving a winding arranged to be on- I ergized at a predetermined speed of the prime mover and a member movable relativel to said rotor comprising an energizing win ing arranged to be connected to said electric circuit at a higher predetermined so speed of the prime mover, said member being arranged to rotate at a speed dependent upon the difference between the fr uencies of the alternator and the circuit, an means I operative with a time delay to effect the dos ing of said switch only when the speed of less than a predetermined value.

14. In an electric system wherein the electromotive 'force of an alternator is to be 99 synchronized with the electromotive force of an electric circuit and wherein a prime mover is provided for drivin said alternator, a switch for connecting t e alternator to the circuit, a member arranged to be driven by said prime mover at a. s eed proportional to the frequency of -the e ectromotive force of the alternator, a relatively movable cooperating member having an energizing winding and arranged to rotate at 1011- a speed proportional to the difference between the frequencies of the electromotive forces of said alternator and said circuit, means adapted to be operated to start said prime mover comprising switching means 10 arranged to connect said winding to the electrlc'circnit at a predetermined s of the prime mover, means controll by said cooperating member operative in re sponse to the rotation thereof to change the speed of the prime mover whereby to bring the s'ameto synchronous speed, and means comprising a time limit relay operative to eti'ect the'closing of said switch only when the speed of said cooperating member is less than a predetermined value.

15. In an electric systemswherein the electromotive force of an alternator is to be synchronized with the electromotive force of an electric circuit and wherein a prime mover is provided for driving said alternator, a switch for connecting said alter- .nator to said circuit, an electromagnetic element-arranged to be driven by said prime mover at a speed proportional to the frequency of the electromotive force of the alternator, means adapted to be operated to start the prime mover and arranged at a predetermined speed thereof to effect the energization of said electromagnetic ele- I high ment, means for controlling the speed of the prime mover, a member arranged to cooperate with said electromagnetic element and having an energizing windingarranged to connected ,to said electric circuit at a er predetermined speed of the prime mover, said member being arranged to rotate at a speed dependent upon the difference between the frequencies of the alternator and. the circuit, means operative by said member to control said speed control means whereby to brin'g the prime mover to synchronous speed, and means operative 'with' a. time delay to effect the closing of said switch only when the speed of said member'is less' than a predetermined value.

16. In an electric system wherein the electromotive force of an alternator is to be "synchronized with the eleetromotive force said circuit and for contr hng of an alternating electric current circuit and mi wherein a prime mover is provided for driving said alternator, a dynamoelectric machine comprising two relatively movable cooperating membeis, one of said members bein arranged to be driven at a speed depen ent upon the frequency of said alter: nator and the other ofsaid members being arranged to rotate ata speed dependent upon the difference between the frequencies of said alternator, and means the speed of said prime mover arranged to becontrolled by said other member to bring said prime mover to synchronous 'speed,

In 'witness whereof, I have hereunto set my hand this 21 day of April, 1923.

ISAAC E. cox. 

